I have a Corsair AX1200 that I'd like to make custom modular cables for. The 24 pin ATX cable that came with it has varying wire gauges, from 16 to 22 AWG. The wires that I'm wanting to replace them with are only made in 18 AWG (UV reactive sheathing). My question is would it be safe to use 18 AWG for all of them, in particular the 16 AWG wires? I know that replacing the 22 AWG wires with 18 AWG should be safe but I'm concerned about the 16 gauge ones. The lengths will be kept the same, I'm neither shortening nor lengthening my cables. Any advice would be greatly appreciated. Thanks!
Sure, 18 gauge wires would be safe for the 24 pin cable.
A modern motherboard has a negligible 12 volt demand. 12 volt demand has been moved to the CPU and PCIe power cables.
Based on a Corsair 750TX which has 18 gauge wiring, the max 5 volt current is 28 amps (140 watts) and the max 3.3 volt current is 30 amps (100 watts). Even a full featured motherboard will not pull more than 60 - 70 watts. Based on real measurements, my old eVGA 680i board pulled about 50 watts at 5 volts. 4 GB of DDR2 RAM at 2.2 volts pulled 6 amps from the 3.3 volt rail. and DDR3 RAM is at least 30% more efficient due to the lower operating voltage.
Thank you jsc. I hope you don't mind a few more questions. I have an Asus P8P67 Pro Rev 3.0 motherboard with a Core i7 2600K and 8GB (2x4GB) DDR3 1600 RAM. That should be okay with 18 gauge wire, right?
Alternatively, I've read somewhere that painting the wires with UV reactive paint may be a viable solution. The paint in question is manufactured to go inside computer cases and is non-conductive. Would that work better in your opinion?